Insulated wall and method of manufacture



June 23, 1964 R. J. CARBARY INSULATED WALL AND METHOD OF' MANUFACTURE IN V EN TOR.

, RICHARD J. CARBARY ATTORNEY United States Patent C) 3,137,900 INSULATED WALL AND METHOD F MANUFACTURE Richard d'. Carbary, La Grange, Ill., assignor to General Electric Company, a corporation of New York iiiled Aug. 1, 1961, Ser. No. 128,536 6 Ciaims. (Cl. Ztl- 35) This invention relates to thermally insulated structures and the method of manufacture thereof, and it is of particular interest with respect to the manufacture of an insulated structure such as a refrigerator door or the like in which one portion may be of relatively good heatconducting material and a second portion may be of relatively poor heat-conducting material.

In refrigerator manufacture, for example, it is the practice to make the door of the cabinet by assembling two panels. The outer panel is usually of steel and provides the front and side walls. The inner panel, which may be formed by various manufacturing methods, is usually of plastic. This inner panel is exposedto the temperature of the interior of the cabinet, which may be from 60 to 100 degrees F. lower than the outside temperature to which the outer door panel is exposed; and to minimize heat flow from the outer to the inner panel, it is common to use low heat-conductivity members, known in the art as breaker strips, to join the respective outer and inner panels. To insure that the door seals snugly against the marginal walls of the cabinet, it is the usual practice to employresilient gaskets adjacent the marginal walls `of the door. With the new emphasis on door latches or door constructions which will open under the relatively light effort applied against the door from the inside-that is, an effort which a trapped child could applyj-the gaskets must be very sof for there is no longer the action of a strong latch to pull the door home. Some manufacturers eliminate latches, and rely on magnetic gaskets which maintain the door in closed position by magnetic engagement with the adjacent cabinet walls.

' Currently, almost all refrigerator door gaskets aresecured to the door by screw-fastened devices. I n manufacture this requires that a workman drive a multiplicity of screws, and an inspection procedure which, among other things, will determine whether or not the screws have been properly applied. When it is necessary for a serviceman to change a gasket in the field, as is sometimes required when after a period of use the soft gaskets take a set which permits air leakage into the cabinet, it is a complex and time-consuming job which is quite likely to arouse the ire of the customer, for his refrigerator must be out of service for an hour or more and the contents may spoil.

It is therefore a principal object of the invention to provide means which combines a low heat transfer breaker strip with l'structure which facilitates the installation of a gasket during manufacture and greatly expedites the removal and replacement of gaskets by servicemen in the field. It is an object of the invention to provide a gasket mounting means within which a refrigerator door gasket or the like may be securely held by friction without the use of screws or adhesives.

It is a further object of the invention to provide a. gasket mounting structure which is particularly adaptable 3,137,900l Patented June 23, 1964 ice to the construction of refrigerator doors using foamed insulation generated within the door after the inner and outer panels have been assembled, and provides means whereby the respective door panels are securely keyed to the solidified body of insulation.

In practicing the invention as applied to a construction in which foam insulation is used, I provide a conventional metal outer door panel having upstanding side walls which terminate in inwardly directed flange portions occupying a common horizontal plane. These flange portions are relatively narrow and define an opening whereby the door, when resting on its outer panel, resembles a basin-like structure. I provide also a conventional inner panel which may be a sheet of plastic shaped by well known vacuum forming technique, by injection molding, or other conventional means. This inner panel has a flat outermost wall portion extending about its periphery, and its longitudinal and transverse dimensions are respectively less'than the longitudinal and transverse dimensions of the opening defined by the outer panel flanges. To bridge the gap between the inner panel and outer panel fianges and also to: provide for the securement of the panels one to the other, I utilize an extruded plastic channel having sidewardly extending flanges which are arranged to grip either or both of the adjacent panel elements. Its exterior and interior walls may advantageously be provided with ribs or other frictional or keying elements.

InV the manufacture of the door, the outer panel is placed on a table, and to the flanges of said panel or to the side wall portions of the inner panel, according to the type'of structure used, I apply the extruded channel member with the channel opening facing outwardly. In this arrangement the body portion of the channel will extend below the surface of the element to which it is applied.

I then introduce into the outer panel a mixture of mate- 1 rials which will produce a foam and will harden into a porous rigid mass. For example, the foam may comprise polyurethane resin employing a low boiling vaporizable liquid such as trichloromonofluoromethane as the foaming agent. By experimentation or otherwise, the proper amount of the mixture to expand into a solidified body to completely fill the hollow door structure is easily ascertainable. Immediately after pouring the foamable mixture into the outer door panel structure, the inner panelis positioned with the channel member in surface engagement with its side wall portions (or with the flange portions of the outer panel if the channel had been applied to the inner panel) and the inner panel braced or supported by applying thereto a back-up member which is secured against release by clamping means or the like.

It is a feature of the invention that as the insulation mass Y develops and fills the hollow door, it envelops the outer wall of the channel member and grips the ribs or other keying devices. The solidified foam insulation thus securely locks the channel within the mass of insulation material and thereby holds the outer and inner panel members in secure position relative to each other. After the completion of the insulation process, a door gasket having a body portion arranged to seat frictionally within the channel structure may be readily applied by simple insertion and without lthe use of fastening devices of any kind. It is apparent therefore that, because the channel structure is securely held as an incident to manufacture and the gasket is only frictionally held within the channel, there is no problem with respect to the removal and replacement of a gasket under field service conditions.

A further advantage of the gasket-receptive channel is that a body of spacer material may be placed between the inner base wall of the channel and the base of the gasket if it be necessary to cause an abnormal projection of the gasket from the channel in selected areas.

Other features and advantages of the invention will be understood from the following detailed description of presently preferred forms, read in connection with the accompanying drawings, in which:

FIG. 1 is an enlarged fragmentary section of a portion of a refrigerator door and a refrigerator cabinet, constructed according to the present invention and illustrating the use of a magnetic door gasket;

FIG. 2 is a fragmentary view of the assembled outer and inner panels with a channel member and gasket member of somewhat different construction;

FIG. 3 is a fragmentary plan view of a corner portion of the door looking at the inside panel thereof showing portions of the channel members in position;

FIG. 4 is a fragmentary side sectional elevation of an inner door panel `in which the gasket channel portion is integral with the door panel; and

FIG. 5 is a somewhat schematic cross sectional view of the outer and inner door panels assembled following the introduction of a charge of insulation material.

Referring now to FIGS. 1 and 2 a refrigerator door 1 comprises an outer panel 2 and an inner panel 3 assembled so as to define therebetween a hollow space completely occupied by a body of solidified foam-type insulation 4. Said foam may be of any of the well known polyurethane resins using trichloromonotluoromethane as the foaming agent. It will be noted that the outer panel 2 is a dish-like structure having a front wall 5, side walls 6 and a relatively short inwardly extending flange 7. It will be understood that the flange 7 is provided about each of the four sides of the panel 2.

The inner panel 3 may be of conventional shape as is now required for the mounting of door shelves (not shown) and the like but has an outwardly extending flat wall portion 8 about its four sides. As indicated in FIGS. 1 and 2, it will be understood that the dimensions of the inner door panel are such that when it is placed relative to the flanges of the outer door panel, a substantial gap will extend about the four wall portions 8 of the inner panel, and the present invention contemplates the bridging of this gap by means of a low thermoconductivity member which affords means for securing the respective panel members relative to the body of insulation material while providing for the easy insertion and removal of a door gasket.

For example, in FIG. 1 there is illustrated a channel structure 10 in which the channel opening faces upwardly, that is, toward the metal facing walls 12 of a refrigerator cabinet. Said walls are arranged to receive the edge walls of a plastic inner liner 13, as is conventional. The channel may he extruded from any of the commonly used materials such as rigid polyvinyl chloride, and in the FIG. 1 form is shaped to have an outwardly extending ilange 14 which will be in overlapping relationship with the side wall 8 of the inner panel and the fork-like walls 15 which snugly receive the inner portion of the liange 7 of the outer panel. Ribs 16 of any suitable shape are provided on each of the outer wall portions of the channel. Interiorly of the channel, the

walls are similarly formed with rib structures so as frictionally to grip the body portion of a gasket. For example, one wall may have a rather large radius curved rib 17 whereas the other wall may have the serrations 18. This configuration is by way of illustration only and is intended to typify a construction in which the channel readily receives a gasket while securing it against accidental outward displacement. 19 represents a resilient i body of material between the gasket and channel, for a purpose later described.

The gasket 20 of FIG. l is of the well known magnetic type in which very flexible side walls 21 support a tubular structure 22 within which is located a continuous strip of magnetic material 23. As is well known, such magnets comprise a rnass of magnetized iron particles contained within a plastic body. The main body portion 24 of the gasket is made compressible by means of the continuous longitudinal opening 2.5 therein, whereby the gasket will readily permit insertion within the channel 10. In channel members provided with longitudinal serrations 18, it may be advantageous to utilize a complementary serration 26 on the adjacent gasket body wall. It is comtemplated that the opposite wall will be plain and yieldable to accommodate the rib 17 following gasket insertion. At the junction of the ribs 21 and gasket body 24, I provide the outwardly extending flexible wings 27 which will extend beyond the forked structure 15 of the channel 10 and also conceal the joint between the panel 3 and the channel 10.

In the embodiment of FIG. 2 the channel member 30 is arranged to have its forked walls 31 engage the side wall portions S of the inner panel and its outwardly extending flange 32 in an overlying relationship with respect to the iiange 7 of the outer panel 2. In other respects the channel configuration may be similar to that illustrated in FIG. 1; that is, it may be provided with appropriate exterior and interior ribs for the purposes of keying with the insulation material and with the gasket. The FIG. 2 gasket 33 is typical of the soft non-magnetic types and has been illustrated as of the form described in Tarleton U.S. Patent 2,880,049, granted March 31, 1959, for Refrigerator Cabinet Structure and assigned to my present assignee. It may be noted in passing that the gasket illustrated in the said Tarleton patent is fastened to the door construction in accordance with the previous generally accepted practice, that is to say, by means of screw-fastened devices.

In FIG. 3 there is illustrated in top plan view, a channel 10 (or 30) to illustrate the inner rib 17 and inner serrations 18 and also to show the mitered joint arrangement of the channels at the corners of the refrigerator door. In FIG. 4 a plastic inner door panel 3a is provided with an integral channel member 10a of keystone shape. It will be noted that this channel portion has the outwardly extending ange 15a which overlies the flange 7 of the outer panel 2. Because of the keystone shape of the channel 10a, it will be unnecessary to provide the interior or exterior ribs.

Referring now to FIG. 5, it will be assumed that the door panel 2 has been fitted with the channel 10 about its four sides. The outer panel is placed on the table of any suitable press, and into the basin-like structure formed by the outer door there has been poured a charge 37 of the foamable insulation-forming mixture. Immediately thereafter and before the foaming mixture has had an opportunity fully to rise within the door panel 2, the outer panel 3 is placed in position with its side wall portions 8 resting upon the outwardly extending flange 14 of the channel 10. It will be noted that the channel i forms a good locating means for the door panel. Thereafter a back-up structure 38 is placed over the door and an appropriate number of clamps 40 positioned and made secure by the dogs or equivalent 41. Ordinarily, to accommodate the mounting means for door shelves in the completed refrigerator door, the inner panel 3 will be provided with a suitable plurality of apertures 42 to accommodate screws or other fastening devices for the shelf mounts. Said apertures provide an advantageous method of venting the interior of the door during the time when the foaming insulation is expanding to completely till the door structure. Therefore, the back-up member 33 may have the illustrated cavities 43 enveloping the aperateneo@ tures 42 and communicating by way of passages 44 to a central venting passage 45.

As an alternate to the venting procedure, the rib portions 3b of the door panel 3 (FIG. 2) may have therein strips 4a of compressible insulation material such as glass fibre, which will accommodate the ultimate expansion of the foam insulation 4.

It will be noted that in the channel arrangement of FIG. 1 the door panel 3 is not in xed relationship to the channel in the manner of the engagement of the outerpanel flanges 7 with the forked wall 15. It may be advantageous therefore to provide at appropriate intervals about the inside surface of the door panel 3 the projecting knobs or elements 46 having external serrations or the like which will be gripped by the foamed insulation as it expands and sets. Thus, in the FIG. 1 form, the channel 10 is securely gripped by the foam insulation 4. The outer panel 2 is secured to the channel 10 by way of the engagement of the forked wall with the flange 7. The panel 8 is securely locked in position by the configuration of the projections 46 and the envelopment thereof by the foam 4.

In the FIG. 2 channel embodiment the inner panel itself is gripped by the fork portion 31 of the channel, thereby making the knob-like projections 46 unnecessary. It will be that apparent that the outer panel 2 is so related to the channel 30, and the channel 30 so keyed within the insulation 4, as to make additional fastening means unnecessary for the outer door panel.

Similarly, it will be observed that in the integral structure of FIG. 4, the outer and inner panels will be securely held together by the solidified body of foam insulation.

Reverting to FIG. 1, the material 19 below the gasket body is illustrative of a resilient spacer strip which may be employed if it is desired to project the gasket more than normally beyond the flange 7 and inner panel 3. This may provide, for example, a convenient way to correct improperly functioning gaskets in field service calls. The material 19 will advantageously be in strip form, cut in the field to whatever length is necesary to accomplish the purpose.

While there has been described what is at present thought to be a preferred embodiment of the invention, it will be understood that it is intended to cover in the appended claims all modifications which fall within the true spirit and scope of the invention.

What is claimed is:

1. A thermally insulated wall structure comprising, in combination, a first panel having upstanding side and end walls and a continuous flange extending inwardly from said walls, a second panel disposed inwardly of said flange and having peripheral wall portions substantially in the plane thereof, solidified insulation material substantially completely filling the space between said panels, means providing a rigid substantially rectangular channel structure of relatively low thermal conductivity material substantially wholly within said insulation material, means including a plurality of rib members extending outwardly from side wall portions of said channel structure for immobilizing the same within said solidified insulation material by an interfitting engagement therewith, said channel structure extending continuously about said second panel and having laterally extending wall means disposed in overlying relation with the wall of an adjacent panel to fix said panel relative to said insulation, and gasket means having a base portion frictionally retained within said channel structure and a resilient head portion outwardly thereof.

2. A thermally insulated wall structure comprising, in combination, a first panel having upstanding side and end walls and a continuous fiange extending inwardly from said Walls, a second panel having fiat wall portions about the periphery thereof, said second panel being disposed inwardly of said flange with the said fiat wall portions substantially in the plane thereof, solidified insulation material substantially completely filling the space between said panels, a rigid member of relatively low thermal conductivity material disposed between said fiange and said second panel to extend continuously thereabout, said member having a substantially rectangular body portion disposed substantially wholly within said insulation material, rib structures extending longitudinally of said body portion and projecting from the sides thereof outwardly into said insulation material to immobilize said body portion therein, wall members extending laterally from said body portion in overlying engagement with said flange and said panel to secure the same relative to said insulation, and gasket means having a base portion removably carried by said body portion and a head portion extending therefrom.

3. A thermally insulated wall structure comprising, in combination, a first panel having upstanding side and end walls and a continuous flange extending inwardly from said walls, a second panel having fiat wall portions about the periphery thereof, said second panel being disposed inwardly of said iiange with the said fiat wall portions substantially in the plane thereof, solidified insulation material substantially completely filling the space between said panels, a rigid member of relatively low thermal conductivity material disposed between said flange and said second panel to extend continuously thereabout, said member having a channel-shaped body portion disposed substantially wholly within said insulation material, the channel opening being in the plane of said second panel, rib structures extending longitudinally of said body portion and projecting from the sides thereof outwardly into said insulation material to immobilize said body portion therein, wall members extending laterally from each side of said body portion in overlying engagement respectively with said fiange and said second panel to secure the same relative to said insulation, and gasket means having a base portion removably disposed within said channel-shaped body portion and a head portion extending therefrom.

4. The combination according to claim 3, in which the inner wall surfaces of said body portion are serrated and the base portion of said gasket is tubular to permit compression thereof for insertion into said body portion and subsequent reaction into frictional engagement with said serrations.

5. The combination according to claim 3, in which the wall member extending from one side of said body portion provides a fork-like structure within which is received the adjacent panel structure.

6. The combination according to claim 3, in which said gasket has flexible wing portions covering the laterally extending wall members of said body portion.

References Cited in the file of this patent UNITED STATES PATENTS 998,464 Cannon July 18, 1911 2,693,009 Beck Nov. 2, 1954 2,786,241 Garvey et al. Mar. 26, 1957 2,924,861 Viets Feb. 16, 1960 

1. A THERMALLY INSULATED WALL STRUCTURE COMPRISING, IN COMBINATION, A FIRST PANEL HAVING UPSTANDING SIDE AND END WALLS AND A CONTINUOUS FLANGE EXTENDING INWARDLY FROM SAID WALLS, A SECOND PANEL DISPOSED INWARDLY OF SAID FLANGE AND HAVING PERIPHERAL WALL PORTIONS SUBSTANTIALLY IN THE PLANE THEREOF, SOLIDIFIED INSULATION MATERIAL SUBSTANTIALLY COMPLETELY FILLING THE SPACE BETWEEN SAID PANELS, MEANS PROVIDING A RIGID SUBSTANTIALLY RECTANGULAR CHANNEL STRUCTURE OF RELATIVELY LOW THERMAL CONDUCTIVITY MATERIAL SUBSTANTIALLY WHOLLY WITHIN SAID INSULATION MATERIAL, MEANS INCLUDING A PLURALITY OF RIB MEMBERS EXTENDING OUTWARDLY FROM SIDE WALL PORTIONS OF SAID CHANNEL STRUCTURE FOR IMMOBILIZING THE SAME WITHIN SAID SOLIDIFIED INSULATION MATERIAL BY AN INTERFITTING ENGAGEMENT THEREWITH, SAID CHANNEL STRUCTURE EXTENDING CONTINUOUSLY ABOUT SAID SECOND PANEL AND HAVING LATERALLY EXTENDING WALL MEANS DISPOSED IN OVERLYING RELATION WITH THE WALL OF AN ADJACENT PANEL TO FIX SAID PANEL RELATIVE TO SAID INSULATION, AND GASKET MEANS HAVING A BASE PORTION FRICTIONALLY RETAINED WITHIN SAID CHANNEL STRUCTURE AND A RESILIENT HEAD PORTION OUTWARDLY THEREOF. 